Scientists awaiting a long-anticipated fishery management plan in New England waters are concerned federal regulators won't take aggressive enough steps to protect the habitat.

The New England Fishery Management Council has been working for several years on a habitat management plan for federal waters from Maine to Rhode Island and is considering a host of options to balance conservation with commercial fishing interests.

One goal of the plan is to review and revise which areas are closed to fishing, according to a draft of the plan. Fishermen, who have struggled with declining catches of groundfish species such as cod and haddock, are closely monitoring the plan.

Conservationists are watching, too, and a group of 138 scientists from around North America has sent a letter to the council stating that it is "deeply concerned that this amendment will fall far short" of adequate protection. The letter states that the scientists - a group that includes university professors, biologists and ecologists - are concerned about "opening closed areas to relieve short-term fish shortages at the expense of future ecosystem recovery."

One of the scientists, University of British Columbia fisheries professor Daniel Pauly, said New England's depleted cod stock would be jeopardized by opening up closed fishing areas.

"The size of the stock is so small that a little thing could push it over the edge," Pauly said. "You must protect as much of the habitat as possible."

The scientists' call for habitat conservation comes as the New England groundfish industry is struggling. The states' fishermen combined to catch 2,247 metric tons of cod in 2013 after catching nearly 8,000 metric tons of the popular fish in 2011.

Federal officials estimate cod spawning in the Gulf of Maine, one of the key areas where fishermen find the fish, to be at only 3 to 4 percent of its target level. Heavy restrictions have been imposed on catching it, meaning prices for local cod have risen in some New England markets.

Regulators need to approve a plan that considers the economic benefit of a healthy fishery, said Terry Alexander, a member of the New England Fishery Management Council and a Harpswell, Maine-based fisherman.

"I think it's important to keep the right areas closed, not just close big swaths of the ocean," he said.

A 90-day public comment period about the federal habitat management plan ends Jan. 8. New England Fishery Management Council members said they expect to vote on the plan in April.